Publicação
Measurement of the top quark pair production charge asymmetry in proton-proton collisions at √s = 7 TeV using the ATLAS detector
| Resumo: | This paper presents a measurement of the top quark pair (tt¯) production charge asymmetry AC using 4.7 fb−1 of proton-proton collisions at a centre-of-mass energy √s = 7 TeV collected by the ATLAS detector at the LHC. A tt¯ enriched sample of events with a single lepton (electron or muon), missing transverse momentum and at least four high transverse momentum jets, of which at least one is tagged as coming from a b–quark, is selected. A likelihood fit is used to reconstruct the tt¯ event kinematics. A Bayesian unfolding procedure is employed to estimate AC at the parton–level. The measured value of the tt¯ production charge asymmetry is AC = 0.006± 0.010, where the uncertainty includes both the statistical and the systematic components. Differential AC measurements as a function of the invariant mass, the rapidity and the transverse momentum of the tt¯-system are also presented. In addition, AC is measured for a subset of events with large tt¯ velocity, where physics beyond the Standard Model could contribute. All measurements are consistent with the Standard Model predictions. |
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| Autores principais: | Onofre, A. |
| Outros Autores: | Castro, Nuno Filipe Silva Fernandes; ATLAS Collaboration |
| Assunto: | Hadron-Hadron Scattering Top physics |
| Ano: | 2014 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | This paper presents a measurement of the top quark pair (tt¯) production charge asymmetry AC using 4.7 fb−1 of proton-proton collisions at a centre-of-mass energy √s = 7 TeV collected by the ATLAS detector at the LHC. A tt¯ enriched sample of events with a single lepton (electron or muon), missing transverse momentum and at least four high transverse momentum jets, of which at least one is tagged as coming from a b–quark, is selected. A likelihood fit is used to reconstruct the tt¯ event kinematics. A Bayesian unfolding procedure is employed to estimate AC at the parton–level. The measured value of the tt¯ production charge asymmetry is AC = 0.006± 0.010, where the uncertainty includes both the statistical and the systematic components. Differential AC measurements as a function of the invariant mass, the rapidity and the transverse momentum of the tt¯-system are also presented. In addition, AC is measured for a subset of events with large tt¯ velocity, where physics beyond the Standard Model could contribute. All measurements are consistent with the Standard Model predictions. |
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